Medical implants such as stents or stent grafts can also be used to open blood vessels to mitigate the effects of plaque buildup, as a scaffold to keep embolic material within an aneurysm, as a flow diverter to limit blood flow to certain regions, or for other reasons.
Stents or other implants are often delivered with delivery devices comprising a sheath or catheter and an elongated pusher within that catheter. Once the distal end of the sheath is located at a desired location, the sheath is either retracted or the pusher is used to push the stent out of the sheath. However, stents are not always deployed in the precise position that physician may intend, and therefore it can be desirable to retract the stent back into the sheath prior to its final deployment.